<template>
  <div class="todo-footer">
    <label>
      <input type="checkbox" v-model="isAllChecked" />
    </label>
    <span>
      <span>已完成{{ complateNum }}</span> / 全部{{ todoList.length }}
    </span>
    <button class="btn btn-danger" @click="clearAll">清除已完成任务</button>
  </div>
</template>

<script>
export default {
  name: "Footer",
  props: ["todoList", "allChecked", "clearAll"],

  computed: {
    complateNum() {
      return this.todoList.reduce((p, c) => (c.done ? p + 1 : p), 0);
    },
    // 全选已完成，利用v-model双向绑定，以及get和set方法
    isAllChecked: {
      get() {
        return (
          this.todoList.every((item) => item.done) && this.todoList.length != 0
        );
      },
      set(newVal) {
        this.allChecked(newVal);
      },
    },
  },
  methods: {},
};
</script>

<style scope>
/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative;
  top: -1px;
  vertical-align: middle;
  margin-right: 5px;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}
</style>